Low-frequency measurement of the tunneling amplitude in a flux qubit

We have observed signatures of resonant tunneling in an Al three-junction qubit, inductively coupled to a Nb LC tank circuit. The resonant properties of the tank oscillator are sensitive to the effective susceptibility (or inductance) of the qubit, which changes drastically as its flux states pass through degeneracy. The tunneling amplitude is estimated from the data. We find good agreement with the theoretical predictions in the regime of their validity.Comment: REVTeX4, 3pp., 3 EPS figures. v2: new sample, textual clarifications. v3: minor polishing; final, to appear in PRB Rapid

A prospective randomized controlled trial of bone metabolism in patients with charcot foot

BACKGROUND: Diabetic neuroosteoarthropathy (DNOAP, Charcot’s foot) - is a progressive destructive inflammatory disease of the osteoarticular apparatus of the foot, untimely and inadequate treatment of which can lead to the formation of gross deformities. More often, DNOAP is unilateral, bilateral lesion is relatively rare. It is not always possible to trace the relationship between the debut of DNOAP with trauma and chronic hyperglycemia. There is data demonstrating the role of individual pro-inflammatory factors in the pathogenesis of DNOAP, however, studies combining the evaluation of various metabolic markers of Charcot’s foot formation are currently extremely poor. AIM: To evaluate the hormonal and metabolic markers of bone formation and resorption in patients with DNOAP and without this diabetic complication. METHODS: A prospective, controlled trial included 70 patients with type 2 diabetes mellitus (37 men and 43 women) who formed 2 groups: group 1 included patients with DNOAP, group 2 was formed by patients with diabetes without foot skeleton damage. All patients underwent a study of 1,25-OH-vitamin D, sclerostin, pro-MMP-1, C-terminal propeptide type 1 collagen (PICP), type 1 collagen, osteocalcin, PTH, 25-OH-vitamin D, beta-cross-slaps. RESULTS: The results of the studies confirmed the presence of vitamin D deficiency in all patients with diabetes mellitus included in the study, revealed the absence of statistically significant differences between the groups in the values of sclerostin, pro-MMP-1; 25-OH-vitamin D, type I collagen, and osteocalcin (p > 0.05). However, significant differences were found in the 1.25-OH vitamin D levels: patients with DNOAP presented the lower rates of 1,25-OH-vitamin D in comparison to control group (p <0.05). Beta-cross and PICP levels were significantly higher in DNOAP patients as well (p <0.05). Those findings show the more severe collagen degradation in patients with DNOAP and can be the genetically predisposed cause of DNOAP development. Though further studies are needed. CONCLUSION: In patients with DNOAP a decrease in 1,25-OH-vitamin D levels was found, as well as the alteration of the synthesis and destruction of collagen (beta-cross-slaps and PICP) compared to patients with diabetes mellitus without osteoarticular disorders

Polariton propagation in weak confinement quantum wells

Exciton-polariton propagation in a quantum well, under centre-of-mass quantization, is computed by a variational self-consistent microscopic theory. The Wannier exciton envelope functions basis set is given by the simple analytical model of ref. [1], based on pure states of the centre-of-mass wave vector, free from fitting parameters and "ad hoc" (the so called additional boundary conditions-ABCs) assumptions. In the present paper, the former analytical model is implemented in order to reproduce the centre-of-mass quantization in a large range of quantum well thicknesses (5a_B < L < inf.). The role of the dynamical transition layer at the well/barrier interfaces is discussed at variance of the classical Pekar's dead-layer and ABCs. The Wannier exciton eigenstates are computed, and compared with various theoretical models with different degrees of accuracy. Exciton-polariton transmission spectra in large quantum wells (L>> a_B) are computed and compared with experimental results of Schneider et al.\cite{Schneider} in high quality GaAs samples. The sound agreement between theory and experiment allows to unambiguously assign the exciton-polariton dips of the transmission spectrum to the pure states of the Wannier exciton center-of-mass quantization.Comment: 15 pages, 15 figures; will appear in Phys.Rev.

New forming method of manufacturing cylindrical parts with nano/ultrafine grained structures by power spinning based on small plastic strains

A new spinning method to manufacture the cylindrical parts with nano/ultrafine grained structures is proposed, which consists of quenching, power spinning and recrystallization annealing. The microstructural evolution during the different process stages and macroforming quality of the spun parts made of ASTM 1020 steel are investigated. The results show that the microstructures of the ferrites and pearlites in the ASTM 1020 steel are transformed to the lath martensites after quenching. The martensite laths obtained by quenching are refined to 87 nm and a small amount of nanoscale deformation twins with an average thickness of 20 nm is generated after performing a 3-pass stagger spinning with 55% thinning ratio of wall thickness, where the equivalent strain required is only 0.92. The equiaxial ferritic grains with an average size of 160 nm and nano-carbides are generated by subsequent recrystallization annealing at 480°C for 30 min. The spun parts with high dimensional precision and low surface roughness are obtained by the forming method developed in this work, combining quenching with 3-pass stagger spinning and recrystallization annealing

Peak Stir Zone Temperatures during Friction Stir Processing

The stir zone (SZ) temperature cycle was measured during the friction stir processing (FSP) of NiAl bronze plates. The FSP was conducted using a tool design with a smooth concave shoulder and a 12.7-mm step-spiral pin. Temperature sensing was accomplished using sheathed thermocouples embedded in the tool path within the plates, while simultaneous optical pyrometry measurements of surface temperatures were also obtained. Peak SZ temperatures were 990 ⁰Cto 1015 ⁰C (0.90 to 0.97 TMelt) and were not affected by preheating to 400⁰C, although the dwell time above 900 ⁰C was increased by the preheating. Thermocouple data suggested little variation in peak temperature across the SZ, although thermocouples initially located on the advancing sides and at the centerlines of the tool traverses were displaced to the retreating sides, precluding direct assessment of the temperature variation across the SZ. Microstructure-based estimates of local peak SZ temperatures have been made on these and on other similarly processed materials. Altogether, the peak-temperature determinations from these different measurement techniques are in close agreement